Stitch regulator of sewing machines



Jan. 22, 1952 PUDELKO 2,583,444

STITCH REGULATOR OF SEWING MACHINES Filed May 8, 1950 x' I, 3 )V 2 d J e h f f Z ew/ r &

e l/l e luvawm H RM MV 7410s; K

Patented Jan. 22, 1952 srlron REGULATOR or SEWING MACHINES V Hermann Pudel ko, Bielefeld, Germany, assignor to Duerkoppwerke Aktiengesellschaft, Bielefeld, Germany, a German company Application ay, 3, 1950, Serial No. 160,646

In Germany May 7, 1949 This invention concerns sewing machines of the type in which the forward movement of the material or the sewing direction can be changed so as to permit forward or backwards stitching as desired.

The first mentioned machines with a simple or single acting arrangement for altering thelength of the stitches are not arranged for the backwards stitching which is necessary when doing darning or securing the end of a seam. With these machines it is usual, when doing backwards stitching such as in darns or securing the end of seams, to slightly lift the foot pressing on the material and draw the material backwards by hand stitch by stitch; or in some cases the material is swung around 180 at the end of a seam.

On sewing machinesincorporating a stitch regulator for forwards or' backwards sewing, the hand lever of the stitch direction regulator is spring loaded or clamped to secure it against involuntary movement. In order to overcome the pressure foot spring pressure when using the stitch direction regulator, a considerable amount of force is now necessary, especially when changing from backwards to forwards sewing which is found particularly unpleasant. This is especially disturbing when doing such sewing as requires frequent alteration of the stitch regulator, such as darning or the securing of the ends of seams.

It is an object of the invention to provide both the described types of machines with an auxiliary attachment which permits the direction of stitching to be changed while the machine is running at any speed, independently of the arrangement fixing the length of the stitch.

According to the present invention, for changing from iorward to backward stitching anauxiliary attachment is provided, adapted to recouple the eccentric driving the feed dog in a position displaced by 180 to its drive. By means of this auxiliary attachment it has also become possible when sewing backwards to alter the tension of the thread so that, for backwards sewing, by turning the feed dog eccentric, the feed dog can operate sooner or later relatively to the penetration of the needle in the work.

The invention will be further described by way of example, with reference to the accompanying drawing, in which:

Fig. 1 is a front view, partially in section to reveal detail, of a sewing machine with a device for reversing the direction of the feed dog and a device for altering the length of the stitches.

Fig. 2 is a detail in longitudinal section and on an enlarged scale showing the turning of the 3 Claims. (Cl. 112-210) direction of movement of the steering and switching mechanism respectively actuating the cloth feed, in connection with the feed eccentric fitted on the main shaft.

Fig. 3 is a view, partly in section, on the line A-B of Fig. 2, showing the control and switching mechanism connected with the main shaft.

In order to be able to change the direction of movement of the feed dog on a sewing machine so that the machine will sew backwards or forwards as desired, separate control mechanisms are made use of in the invention and connected to the known feed dog eccentric (indicated at h) of the feed dog. The stitch regulator is indicated at c. The effective throw of the feed dog driven by the eccentric is controlled by the regulattor in known manner.

In the present arrangement there fits on the driving shaft b carrying the feed dog eccentric h an axially displaceable sleeve d loosely mounted on the same, and a guide body e adjustably secured thereto which is mounted next to the feed dog eccentric It provided with a driving pin 1. The driving pin may be fitted with a small spring or a similar damping device in order to cushion the shock when changing from forwards to backwards sewing.

The sliding sleeve 01 ismovable on the shaft b in the axial direction and is prevented from turning with the said shaft by a threaded bolt 12'' which passes through a slit in the arm of the machine. Over the circular fiange d" of the sliding sleeve (1 the notched end of an operating spindle e engages which spindle is carried in the body of a sleeve e axially movable and secured against turning about its own axis by a pin 2. The

retention bolt e remains slidingly engaged with the circular rim d" while the shaft b rotates.

A retention bolt 6" having a guide pin 2' displaced angularly by an angle of to the retention bolt e is likewise arranged to be axially movable in the sleeve e and is connected with the retention bolt e by a lever g secured at the point e so as to pivot about said point.

The pin z is displaceable axially in a slit e in the sleeve e. By moving the sliding sleve d in one direction the retention bolt e" comes into range of the driving pin f of the revolving feed dog eccentric h to rotate with the shaft b, and when the sleeve d is moved in the opposite direction drive is taken by the retention bolt 2'.

By the alternating switching of position of the retention bolts 6 and e" two positions of the feed dog eccentric h are obtained, spaced by 180 apart, whilst the machine is running, whereby the feed direction of the feed dog of the machine changes from forwards to backwards sewing, and vice versa.

For moving the sliding sleeve d a, Bowden wire 'In may, by Way of example, be used, which is connected with the sliding sleeve :1 so that its operative press button m or similar means may with advantage be placed in immediate proximity to the needle head of the machine. The already mentioned bolt 02" is firmly connected to a crank 9' and is held in the usual manner in its final position in the opposite direction to that of the arrow by a pressure spring Z which is fixed between the crank and a projection k adjustably mounted on the machine in a position so that the sewing machine initially is in a position for forward sewing.

The actuation of the switching and control mechanism is effected by a light pressure of the finger on the press button m of the Bowden wire or against the crank 1 whereby the sliding sleeve d. ismoved in the direction of the arrow by which the retention bolt e is moved into the path of the catch I- while at the same time the retention bolt e" is withdrawn from the path of the catch 1. By the turning of the shaftb the feed dog eccentric h first comes to, a standstiiluntil the catch '1 belonging to same is caught by the retention bolt e. By the turning of the feed dog eccentric h 180 relatively to the driving shaft b the machine is then set for feeding the work backwards so long as the pressure of the finger against the crank 1' or on the press button m is maintained.

The. pressure spring Z is with advantage made easily removable or the crank 7 and respectively the. press button m. can by any suitable known method be locked in position to make prolonged sewing in a backwards direction possible.

' Changing, the machine from forwards to backwards sewing can consequently be effected quite independently of, any known length-of-stitch regulating device and this merely by the use of a very easily operated press button which may be situated in the immediate proximity of the part being sewn. Among other advantages this is of the greatest importance when the machine is to perform darning or seam locking work with a constant changing from backwards to forwards sewing, for the short stretches to be worked.

The mechanisms effecting the control are exceptionally simple as regards their construction and they can without difficulty be adapted for other types of machines than those described.

I claim;

1. A sewing machine including in combination a stitch forming mechanism, a driving shaft, a

reciprocating feed dog, an eccentric loose on said driving shaft, means connecting said eccentric with said feed dog, a first sleeve axially displaceable on said driving shaft, a second sleeve fixed to said driving shaft, a pair of driving pins displaced by axially guided on said second sleeve,

a pivoted leveryconnecting means between said lever and said pins, a coupling between said pivoted lever and said first sleeve, and means to displace said first sleeve to couple one or other of said driving pins to said eccentric as said first sleeve is displacedaxially on the driving shaft.

2. A sewing machine including in combination a stitch forming mechanism, a reciprocating feed dog, a driving shaft, a cam free on said shaft, means comiecting said cam to said feed dog, a sleeve displaceable on the said driving shaft, control means for said sleeve operated remotely from the needle head, means to prevent said sleeve rotating with the driving shaft, a second sleeve fixed on said driving shaft, a pair'rof driving pins axially displaceable. in said second sleeve and disposed at180, to one another, and means coupling the said pins with said axially displaceable sleeve so that one driving pin only at, a time couples said second sleeve withsaid' cam.

3'. A sewing machine including in combination a stitch forming mechanism, a reciprocatingfeed dog, a driving shaftsa cam free on said shaft,

REFERENCES CITED The following references are of record in the file of this patent: g

UNITED STATES. PATENTS Date Number 7 Name 968,329 Dawson Aug. 23, 1910 1,605,937 Grieb Nov. 9, 1926 2,023,868 Bouchard Dec. 10, 1935 FOREIGN PATENTS Number Country Date- 19385 Great Britain of 1906 

